It is known to provide a hydraulic circuit to conduct the flow of hydraulic fluid so as to allow a motor of a vehicle, such as a mower, to be operated. Typically, these circuits are provided with a series of valves and switches to direct the flow of that liquid, whereby pressure associated with that flow to that motor permits its device, a blade as in the case of a mowing tractor, to move.
In providing these circuits, at least two designs have been used to accomplish the above. A first design has included providing a separate circuit for each of the motors, and thus the devices whose motion they control. A second design has included providing a single circuit and connecting each of the motors in series whereby flow to a particular motor can be accomplished through control of an associated valve manifold or collection of valves within the circuit.
With each of the above designs, disadvantages exist. In the case of providing a separate circuit for each of the separate motors, each circuit would require its own pump and control valve whereby the cost of doing so disfavors providing an economical product to the consumer. In the case of providing a circuit having each of the motors connected in series, efficiency, or the ratio of the work output to the work input across a system, is often decreased. This decreased efficiency results from drops in pressure across the valves which control the direction and function of flow and pressure through the circuit. These valves exist to regulate, as stated above, the pressure across the circuit when it is necessary to control the flow of hydraulic fluid to a first motor while preventing flow to one or more of a series of motors when it is desired to only operate one or a combination thereof. As fluid passes over these valves, the system experiences a drop in fluid pressure causing the system to be less efficient than it could otherwise be. Additionally, cost disadvantages also exist in this design due to the provision of these control valves.
Thus, it would be beneficial to provide a circuit which could allow for the control of multiple motors in a series circuit while doing so with low parasitic loss, or the pressure drop across the manifold, and a minimal number of valves within the manifold as a result of how fluid is directed to a particular motor.